In recent years the present inventor has been attempting to improve upon the design of containers or dispensers for two-component epoxy resin adhesives. One product of his early work is the design of dispenser disclosed in his co-pending U.S. Pat. application Ser. No. 537,332, filed Dec. 30, 1974 now U.S. Pat. No. 3,952,920. Although that design is believed to be an improvement in comparison with much of what has been marketed, experience and insight gained since that disperser was designed have led the present inventor to see that such a dispenser should be more compact, durable, easy to assemble and easy to adapt to dispensing different product than it is. This realization led to a redesign effort which has produced the present invention.
During the development of the new dispenser, the present inventor has become aware of the following patents of at least general interest to the subject:
______________________________________ Patentee Patent No. Date of Issue ______________________________________ Thompson 2,253,151 August 19, 1941 Maillard 2,826,339 March 11, 1958 Herman et al 3,117,696 January 14, 1964 Van Sciver II 3,159,312 December 1, 1964 Nielsen 3,166,221 January 19, 1965 Creighton, Jr. et al 3,311,265 March 28, 1967 Creighton, Jr. et al 3,323,682 June 6, 1967 James L. Cannon 3,767,085 October 23, 1973 ______________________________________
It is common for dispensers for multi-component products such as two component epoxy resin adhesives to be sold in a filled condition, wherein the cylinders are largely full of product. Accordingly, the pistons are at the ends of the cylinders and the piston rods extend substantially from the cylinders. The pistons are pushed in as the product is dispensed, thus shortening the original length of the dispenser. The original length of the dispenser can be objectionable from two aspects. Firstly, the longer length of the dispenser necessitates a longer length of packaging, with attendant greater cost therefore. Secondly, the extended piston rods are vulnerable to being broken by bending stresses applied normally of the longitudinal axes thereof, for instance, when something heavy is dropped when its piston rods are fully extended.